1) Look at it and decide if it's testing, shooting, or if it's a new car at all. Often you may just be excited and misinterperate the lines of a current car to be a new one.

2) Do you have a Camera? Size up the situation. We don't want you to put yourself in harm's way to shoot a car. Or, for that matter, harm other people. It's best recommended that if you have a passenger, make them photograph it or record information from it. Sometimes you can follow it to its destination

3) record license plate types, numbers, state (or country) the description of the vehicle (car, pickup, SUV, MPV, # of doors, possibly the model if you know it for sure). (do this especially if you don't have a camera). In the US, Manufacturers have numbers which are put on to ALL of the "mfr" license plates. This can sometimes be used to identify a model. I don't know about internationally.

4) Network. As soon as you can, come to CSS or another site which people would be willing to hunt such a car down. Report where the car was, what it was doing, the direction it was headed, and from there usually there can be one or two other members in a decent radius who are willing to go out and hunt it down. even if you can't take pictures, report as much as you can and someone else may be able to.

Don't just say "I saw this car" and disappear. It's rare to see one, and by networking we are best able to ensure that this information, and website, will stay on the web.

Might also want to mention that some engineers will react to a camera aggressively. Attempts to block you with chase vehicles or run you off the road aren't unheard of. Of course don't be surprised if THEY start chasing YOU just to try and scare you off.

Funny you should mention that. Years ago, I was cruising on the road taking pictures on a scenic route. When all of the sudden a car slowed down and tried to get me killed by forcing me off the road. Whether or not it was directed b/c they THOUGHT I was trying to take pictures of their car (might be a covered upcoming car), I honestly couldn't remember (anymore) but I was minding my own business and was just trying to take scenic pictures for my collection - I never even pointed my lense on the car, to my knowledge. but certaintly I was pissed for their actions Long story short, they tried to get me off the road so I would stop following them (although their actions and intentions almost got me killed). But they failed. I got in front of them and stopped short (hit my brakes hard) and while trying not to hit me, they almost went off the road themseleves. Payback is a b***h

Might also want to mention that some engineers will react to a camera aggressively. Attempts to block you with chase vehicles or run you off the road aren't unheard of. Of course don't be surprised if THEY start chasing YOU just to try and scare you off.

Living here in Phoenix, AZ we have our share of prototypes around the valley and state. When I was up in Northern AZ skiing (yes it snows in AZ) I happen to see the new VW Bettle with its ugly black trap on it. I started to take pics, and one of the enginers came up to me in a very THICK german accient DEMANDING me to stop taking pics. They were having car problems. I explained to him that in AMERICA, I can take pictures of what I want, and also explained to him that I'll keep taking pics as along as I like. The man wouldn't get out of my face. Local police saw this and walked up, I explainted to the police officer what was going on and this person was trying to intimadate me in stop taking pic of that new VW Bettle over there. Come to find out, that Cop was a car nut too, and told the Engineer to back away...